Activists say Syrian government forces have pounded targets in the opposition stronghold of Rastan, and at least six people have been killed elsewhere, during violence related to the country's anti-government unrest.

The Britain-based group also said an explosion near Damascus killed three people.

Watch unverified video of shelling in Rastan
Meanwhile, Lebanon's foreign minister said 11 male Lebanese pilgrims who were kidnapped while traveling through Syria this week will be freed soon. Adnan Mansour said Wednesday that negotiations for their release were ongoing, but he did not disclose who is holding the men.

On Tuesday, gunmen stopped a bus carrying Lebanese Shi'ites traveling through Syria after visiting shrines in Iraq. The gunmen freed several dozen women who were on the bus.

Relatives greeted the women late Tuesday as they arrived at a Beirut airport.

One woman told the Reuters news agency the captors claimed they were part of the opposition Free Syrian Army. Members of the Free Syrian Army denied the group was responsible for the incident.

Russian Foreign Minister Sergei Lavrov warned Wednesday that the "tangible threat" of violence in Syria spilling into Lebanon could "end very badly." He blamed the violence between Sunnis and Shi'ites there on "artificial" agitators.

U.N. monitors in Syria continue efforts to monitor a fragile cease-fire brokered by international envoy Kofi Annan in April. U.N. officials estimate that more than 10,000 people have been killed since Syria's anti-government unrest erupted more than a year ago.